After a pregnancy with a normal outcome what are women's perception and knowledge of prenatal tests performances? A survey was carried out during 1990, in the Bouches-du-Rhône area, on a representative sample of French speaking women who had just delivered a normal liveborn. The participation rate was 80% and the mean maternal age was 28.9. On average, 5 (4.7-5.1) prenatal ultrasound scans were carried out per pregnancy and 93% of the women thought that the main interest of this exam performed during the 4-5th month of pregnancy was to confirm that the foetus was normal; only 9% answered that when the scan was normal one could be sure that the fetus was normal. Among those responding, 87% were informed about the existence and the goal of amniocentesis: media were the first source of information about the test in 42%. The level of education was the major determinant of women's knowledge and this factor should be taken into account by the practitioner during the prenatal surveillance.